Core orientation

ABSTRACT

An upper end ( 10 ) for the inner tube of a core drill has a marking device comprising a pendulum ( 350 ) or hard ball ( 30 ) which runs in a circumferential track ( 24 ). The marking device adapted to be carried within a tubular upper end casing ( 12 ) which surrounds a spindle ( 11 ) which supports the inner tube of the drill. An indent washer ( 25 ) is positionable below the marking device and is oriented relative to the casing. When the upper end ( 10 ) is lifted, the marking device is driven into contact with the washer ( 25 ) and makes an impression. The orientation of the impression reveals the orientation of the drill. The impressioned washer ( 25 ) can be used to assist in noting or marking the core orientation after the drill is removed from the earth.

FIELD OF THE INVENTION

This invention relates to core drilling and more particularly toapparatus and methods for determining the original orientation of a coresample after it has been drilled, separated and pulled out of the earth.

BACKGROUND ART

Many forms of geological survey depend on core drilling for samples.Some surveying requires that the orientation of a core be determinedaccurately and reliably. In many situations the angle of thelongitudinal axis of the core drill relative to the “plane” of the earthat the drill site is other than 90 degrees. This is the drilling angleand it may be ascertained in a number of ways. It is sometimes alsoimportant to determine, after removing the core for inspection, therotational orientation or compass orientation of the core samplerelative to the surrounding terrain from which it was extracted. Knownprior methods are not reliable, particularly at low angles ofinclination from the vertical.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an apparatus for use withcore drilling devices which includes a hard ball which runs in acircumferential track. The ball and track are adapted to be carriedwithin a tubular upper end casing, which surrounds the spindle whichsupports the inner tube of the drill. An indent washer is positionableabove the track and ball and is oriented relative to the casing. Aspring supports the washer above the ball. When the upper end is lifted,the ball is driven into contact with the washer and makes an impression.The orientation of the impression reveals the orientation of the lowestpoint in the track. The impressioned washer can be used to assist innoting or marking the core orientation after the drill is removed fromthe earth.

In one preferred embodiment of the invention, the washer is formed withan alignment hole. The upper end casing supports a pin which extends inthe direction of the drill rotational axis. The pin passes through thehole to maintain the washer in a fixed alignment with the casing.

In another embodiment of the invention the spindle is split into upperand lower segments, the lower segment having a flange which bears onthrust bearings.

In another embodiment of the invention, a laser pointer system is usedto transfer orientation information to a core which has been drilled inconjunction with a ball, track and washer device as disclosed withreference to the present invention.

It is yet another object of the invention to provide an apparatus foruse with core drilling devices which includes a pendulum and backingplate which together form a ball and socket joint. The pendulumterminates in the joint which makes an impression in the indent washerhaving a known orientation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section of an upper end of a core drill inner tube;

FIG. 2 is a cross section of the track;

FIG. 3 is a perspective view of the indent washer;

FIG. 4 is a cross section of the casing of the upper end; and

FIG. 5 is a perspective view of an inner tube and upper end, showing theuse of the levels and indent washer in marking the core;

FIG. 6 is a cross section of another embodiment of the invention;

FIG. 7 is an enlarged view of the coupling portion of the embodimentshown in FIG. 6;

FIG. 8 is an exploded perspective view showing the ball, track andindent washer;

FIG. 9 is a front elevation showing an alignable laser stand and clamp;

FIG. 10 is a side view of the device depicted in FIG. 9. A laser pointeris held by the device;

FIG. 11 is a laser mask or image intensifier which is used incombination with a laser pointer according to the teachings of theinvention;

FIG. 12 illustrates a front elevation and a cross-section of a discreader;

FIG. 13 illustrates a front elevation and a side elevation of a corereader;

FIG. 14 illustrates laser assisted marking of a core sample;

FIG. 15 is a cross section of an upper end of a core drill inner tube;and

FIG. 16 is a cross section of the pendulum arrangement and disk.

A core drill usually comprises and outer tube and an inner tube. Theouter tube is rotated and transmits rotational power to a cutting head.A drill bit on the cutting head forms a core which rises up through theinner tube as the drill progresses into the earth or substrate. Theinner tube and separated core may be lifted up through the outer tube bylowering a latching body through the outer tube and latching onto aspindle carried by the upper end of the inner tube. The latching body islowered on a steel cable and engages the upper end of the spindle.Tension on the rod string is translated, by a core lifter within thedrill, into a compressive force which acts to fracture the core andseparate it from the substrate. The separated core can then be lifted,within the inner tube, by the cable attached to the upper end.

The present invention has been devised to create a valuable and accuraterecord of the compass orientation of the core at the moment ofseparation.

As shown in FIG. 1, an upper end 10 includes a spindle 11 a casing 12and a shield 13. Threads 14 at the lower end of the shield engage theupper threads of the inner tube of the core drill. The spindle 11 passesthrough the plug 15 which caps the top of the casing 12. A compressionspring 16 is trapped between the plug 15 and a nut 17 which is threadedon to the spindle 11 and secured thereto by pin 18. The lower end of thespindle 11 passes through a bronze bushing 19 and terminates in athreaded stub 20.

When the rod string is raised, the spindle 11 is placed into tension. Asshown in FIGS. 1 and 8, this causes a nut 21 threaded onto the stub 20,to bear against a washer 22 and consequently onto a track 23. The track23 surrounds the spindle 11 and faces upwardly or away from the threads14. A groove 24 is formed in an upper face of the track. The groove 24,when the track is installed, also surrounds the spindle 11. An indentwasher 25 is positioned between the track 23 and the lower end of thecasing 12. A non-magnetic steel or other non-metallic hard ball 30 rollsfreely in the groove. The diameter of the ball is slightly larger thanthe depth of the groove 24. In all non-vertical drilling, the track 23is tilted. When the track is tilted, as in the case of non-verticaldrilling, the ball rolls to the lowest point in the plane of the groove24. The track 23 is shown in FIG. 2.

Until the track 23 is brought into the proximity of the lower end of thecasing, the indent washer 25 and the track 23 are kept apart by a spring26. The spring keeps the indent washer 25 in contact with the lower endof the casing 12. The indent washer 25 (shown in FIG. 3) is formed froma relatively soft metal such as copper or brass that can be impressed orindented with a steel ball. The indent washer has a central opening forreceiving the spindle 11 and an alignment hole or pilot 29.

As shown in FIG. 4, the lower end of the casing is fitted with a pin 27.The pin 27 extends in the direction of the drilling axis 28 and extendsinto the pilot or hole 29 formed in the indent washer 25. This keeps therotational or compass orientation of the indent washer 25 indexed orfixed, relative to the casing 12. The pin 27 does not interfere with therolling of the ball in the groove.

When a core is being separated by raising the rod string, the spring 26compresses as the track 23 is brought toward the indent washer 27.Before contact, the ball 30 has rolled to the lowest point in the groove23. Eventually, the ball becomes trapped between the track 23 and theindent washer 25. Further tension in the rod string causes the ball 30to be driven into the surface of the indent washer 25. This action makesan impression or indent in the washer 25 and the indent is known to beformed at the time the core is separated. When the drill is other thanabsolutely vertical, the angular (or “compass”) position of theimpression marks the bottom or lowest (vertical) point in the groove 24and therefore in the plane of the washer 25. Both the groove 24 and thewasher 25 are perpendicular to the long axis of the drill.

Because the indent washer 25 is pinned to the casing, its orientationrelative to the casing is known. Thus, the impression can later berelated to a reference mark or groove 31 formed on the outer surface ofthe casing. This is shown in FIG. 5.

FIG. 5 show how the core's orientation is determined. In this example,the pin 27 and reference groove or mark 31 are aligned during themanufacture of the casing 12. To be exact, the reference mark defines aplane through the drill axis 28. Preferably and conveniently, the pin isformed in this plane (on the same side of the centreline 28 as the mark31). The pin and reference mark 31 need not be in the same plane so longas the angular relationship of the two different planes is known. Thisrelationship allows the location of the alignment hole 29 in the indentwasher 25 to be related to the location of the reference mark 31.

This means that the indent washer 25 can be removed after drilling andthe indent washer 25 can be used to mark the bottom or low point of thecore. This is done by laying the re-assembled top end 10 and inner tube40 horizontally and rotating them together until the reference mark 31faces straight up. To do this, a specially adapted level 41 is used.

The level is in the form of a saddle 44 which conforms to thecircumference of the upper end 10. The level includes a centralreference mark 42. A spirit level or other levelling device 45 attachedto the saddle indicates when the reference mark 42 is at its verticalmaximum. When the reference mark 42 is at its maximum and also alignedwith the reference mark 31 on the casing 12, the reference mark 31 isknown to be in a vertical plane which passes through the drill axis 28.Next, the same or a second level 43 is used to note the vertical maximumof the lower end of the inner tube 40 and therefore of the core samplewithin. By aligning the hole 29 of the indent washer 25 with theindicated vertical maximum of the lower end of the inner tube 40, theimpression 32 can be used to indicate where to mark an index point ontothe core.

The index point indicates the location of the “bottom” of an inclinedslice of the core sample. It should be apparent that an imaginary linewhich passes radially from the drill axis 28 through the index pointdefines the compass orientation of the core. This is because theinclination of the drill axis in the earth can be related to a compassdirection. This may be done before, during or after drilling byobserving the compass orientation of the vertical plane which containsthe drill axis 28 at the cutting head at the time when the core isseparated.

In order to minimise wear on the bushing 19 an alternate embodiment ofthe invention is contemplated. As shown in FIG. 6, the spindle 110 issplit so that the lower portion 111 of the spindle rotates independentlyof the upper portion 112 of the spindle. Tension is transmitted from theupper portion 112 to the lower portion 111 by a coupling 113. Thecoupling 113 is at one end threaded to a lock nut 114 and serves torestrain the lower portion of the spindle 111 between a pair of thrustbearings 115, 116. The lock nut 114 is threaded onto the bottom end ofthe upper spindle 12 and has a threaded exterior to engage the coupling113.

The lower portion of the spindle 111 carries an integral flange 117which is trapped by the coupling but which rotates freely within it.Ball bearings 118 support the lower portion 111 within the coupling 113.The coupling arrangement allows the lower portion 111 to rotateindependently of the upper portion 112. This arrangement minimises therotation of the lower portion 111 and minimises wear on the seals 120,preferably two in number, which seals prevent grease, water and mud frominterfering with the operation of the track, ball and washer arrangement125.

In order that orientation information can be more efficientlytransferred to the core sample, an optional laser pointer system isprovided (see FIGS. 9-14). As shown in FIG. 9, the laser pointer systemincludes a laser mount 200. The mount 200 includes a tube clamp 201. Theinside diameter 202 of the tube clamp 201 is adapted to encircle anouter circumference of an outer tube 203 (see FIG. 10). The clamp 201also includes an exterior hinge 203 and a tensionable fastener 204. Whenthe fastener 204 is loosened, it may swing out of position (see arrow)205 for facilitating installation and removal from the tube 203. Theinside diameter 202 of the clamp 201 also includes a key 206 which isadapted to fit into the alignment groove 207 which is formed on theexterior of the tube 203. The laser mount 200 further includes apedestal 208 which extends from the clamp 201 to an adjustable pivotinglaser retainer 209. The retainer 209 is affixed to the pedestal 208 andallows for vertical only adjustment of the beam produced by the laserpointer 210. The pointer 210 is held by a second clamp 211 which isadapted to allow easy insertion and removal of the pointer 210.

The laser pointer system may be utilised once a core drilling operationhas been completed, and the core has been broken and removed from thedrill hole. The tube is removed as usual and placed on a horizontalrack. The tube 203 is placed on the rack in a position where the groove207 in the back end is facing up. The laser mount 200 is then positionedover the groove with the key 206 located in the groove 207. The mount isthen locked in place with the fastener 204. The laser beam is adjustedin the vertical plane owing to the adjustability of the retainer 209.The laser is manipulated until the dot of light produced by the laser(usually red) impinges on the core or the end of the core lifter case asrequired. The fasteners 212 on the retainer are then tightened therebysecuring the laser pointer in position.

Next, an image intensifier or mask 215 as illustrated in FIG. 11 is slidover the lifter case and lined up with the centre of the laser dot.Because the slot 216 in the V-shaped mask 217 is narrower than thediameter of the laser dot, a thin line of laser light will appear on thecore or core lifter case. The laser light exiting the image intensifier215 corresponds with the location of the index groove 207 and with thehole 29 in the indent washer 25 (so long as the relationship between theindex groove 207 and pin 27 is known). Using a sharp pencil a thin markis placed on the core where indicated by the line of laser light asshown in FIG. 14.

Next, the core is removed from the tube and placed on a tray or markingrack. Then, the indent washer is removed from the drilling apparatus. Ameasurement is then made of the angle between the washer's alignmenthole 29 and the indent mark (for example 32). This may be convenientlyachieved using a measuring device of the type illustrated in FIG. 12.

As shown in FIG. 12, the disc reader 220 preferably includes ameasurement ring 221 affixed to a disc-like base 222. The washer fitswithin the central opening 223 of the ring 221 and may optionally besupported by the base 222. When the hole 29 of the washer 25 is alignedwith the hole 224 of the reader 220, the angular displacement of theindent 32 can be read directly from the measuring ring 221.

Next a core reader 230 (shown in FIG. 13) is placed over the end of thecore. The zero mark 231 is oriented with respect to the line orimpression made by using the laser pointer on the core. Using themeasurement produced by the disc reader 220 the angular displacement ofthe indentation can then be marked or transferred directly onto the coreusing the measurement ring 232 of the core reader 230. Note that themeasuring ring 232 of the core reader 230 is affixed to a cylinder 233whose inside diameter 234 is adapted to slide over the core.

Another embodiment of the invention is depicted in FIGS. 15 and 16, thisembodiment ups the type of indent washer previously described. In orderto cope with low angles of inclination from the vertical, a pendulum isused.

As shown in FIG. 15, an upper end 10 includes a spindle 311 a casing 312and a shield 313. Threads 314 at the lower end of the shield engage theupper threads of the inner tube of the core drill. The spindle 311passes through the plug 315 which caps the top of the casing 312. Acompression spring 316 is trapped between the plug 315 and a nut 317which is threaded on to the spindle 311 and secured thereto by pin (notshown). The spindle 311 is split so that the lower portion 320 of thespindle rotates independently of the upper portion 321 of the spindle.Tension is transmitted from the upper portion 321 to the lower portion320 by a coupling 322. The coupling 322 is at one end threaded to thelock nut 325 and serves to restrain the lower portion of the spindle 320between a pair of thrust bearings 325, 326. The lock nut is threadedonto the bottom end of the upper spindle 321 and has a threaded exteriorto engage the coupling 322.

The lower portion of the spindle 320 carries an integral flange 330which is longitudinally trapped by the coupling but which rotates freelywithin it. Ball bearings 339 support the lower portion 320 within thecoupling 322. The coupling arrangement allows the lower portion 320 torotate independently of the upper portion 321. This arrangementminimises the rotation of the lower portion and minimises wear on theseals 331, preferably two in number, which seals prevent grease, waterand mud from interfering with the operation of the pendulum arrangement340.

As shown in FIGS. 15 and 16, the pendulum arrangement 340 comprises amounting plate 341 which is attached to the shaft retainer 342 by a setscrew 343. The mounting plate 341 also includes a central opening forslidably receiving the lower portion 320 of the spindle. The mountingplate 341 also receives and supports a mounting post 344 which in turnaffixes to the pendulum backing plate 345. The backing plate 345 mayattach to the post 344 by a fastener 346 or by any other convenientmeans. The backing plate 345 includes a generally hemispherical socketor recess 347 and removably receives a pivot plate 348. The pivot plate348 affixes to the backing plate 345 and includes a central opening 349which prevents the pendulum 350 from escaping. Together, the opening 347in the backing plate 345 and the opening 349 in the pivot plate 348permit the spherical end 351 to pivot about its centre 352. Thus, thebacking plate 345 and the pivot plate 348 comprise a socket and togetherwith the generally spherical end 351 of the pendulum 350 form a ball andsocket joint.

The pendulum 350 further comprises an enlarged bulb 353 and a shortshaft 354 which connects the bulb 353 to the spherical end or ball 351.A terminal end of the bulb 353 forms a conical point 355 which iscapable of making an indentation or impression in the indent washer 356.The pendulum is thus very rigid axially, but free to swing. The indentwasher 356 is retained in a known orientation by the indent washer mountplate 357 which is in turn restrained by a circumferential groove orslot 358 in the needle chamber 359. The needle chamber 359 comprises agenerally cylindrical body which is affixable to the stub shaft or lowerportion 320 by a socket screw 360. An opening 361 in the upper wall ofthe needle chamber 359 allows the mounting post 344 to slide withoutbinding. Thus, when the lower portion of the spindle 320 is placed intension, the replaceable indent washer 356 is drawn toward the point 355of the pendulum 350. Thus, the impression made by the needle 355 makesan impression whose radial orientation on the indent washer 356 isindicative of the compass direction of inclination while the distance ofthe indent from the centre 362 of the disc is indicative of the degreeof inclination.

It will be apparent that the invention has been described with referenceto certain details of construction and that these details should beinterpreted as examples and not as limitations to the scope of theinvention.

What is claimed is:
 1. An upper end for the inner tube of a core drillcomprising: spindle supported within a cylindrical casing forreciprocating motion and biased, by a first spring in the casing, suchthat tension on the spindle overcomes the bias; a circumferential tracksurrounding a lower end of the spindle, the track facing upwardly; aimpressionable washer surrounding spindle above the track and indexed tothe casing; a ball in the track facing the washer, and a second springwhich biases the track away from the washer but allows the impression tobe made when the spindle is tensioned.
 2. An upper end according toclaim 1, wherein: a lower end of the spindle carries a pin which engagesa pilot formed in the washer.
 3. An upper end for the inner tube of acore drill comprising: a spindle supported within a cylindrical casingfor reciprocating motion and biased, by a spring in the casing, suchthat tension on the spindle overcomes the bias; bushings at a lower endof the casing to support the spindle for reciprocating motion; acircumferential track surrounding a lower end of the spindle, the trackfacing upwardly; an impressionable washer surrounding the spindle abovethe track and indexed to the casing, and a ball in the track facing thewasher and which, when the spindle is tensioned to overcome the bias ofthe spring, makes an impression on the washer.
 4. An upper end accordingto claim 3, wherein: a lower end of the spindle carries a pin whichengages a pilot formed in the washer.
 5. An upper end for the inner tubeof a core drill comprising: a spindle supported within a cylindricalcasing for reciprocating motion and biased, by a spring the casing, suchthat tension on the spindle overcomes the bias; a circumferential tracksurrounding a lower end of the spindle, the track facing upwardly; animpressionable washer surrounding the spindle above the track andindexed to the casing, and a ball in the track facing the washer andwhich, when the spindle is tensioned to overcome the bias of the spring,makes an impression on the washer,  and wherein: the spindle is splitand has upper and lower portions; the two portions are joined by acoupling; the lower portion rotates independently of the upper portion;and the coupling transmitting tension from the upper portion to thelower portion.
 6. An upper end according to claim 5, wherein: thecoupling supports thrust bearings which impose on an integral flangeformed on the top of the lower portion.
 7. An upper end according toclaim 6, wherein: a lower end of the casing supports seals between thespindle and the casing.
 8. An upper end according to claim 7, wherein:the coupling supports two thrust bearings, one located above the flangeand one below the flange.
 9. An upper end according to claim 5, wherein:a lower end of the spindle carries a pin which engages a pilot formed inthe washer.
 10. An upper end for the inner tube of a core drillcomprising: a spindle supported within a cylindrical casing forreciprocating motion and biased, by a spring in the casing, such thattension on the spindle overcomes the bias; a circumferential tracksurrounding a lower end of the spindle, the track facing upwardly; animpressionable washer surrounding the spindle above the track andindexed to the casing, and a ball in the track facing the washer andwhich, when the spindle is tensioned to overcome the bias of the spring,makes an impression on the washer,  and wherein: the spring surroundsthe spindle and extends between an upper extent of the casing and a nutwhich is threaded onto the spindle.
 11. An upper end according to claim10, wherein: a lower end of the spindle carries a pin which engages apilot formed in the washer.
 12. A method for determining the orientationof a drilled core relative to a substrate comprising: (i) drilling acore from a substrate with a core drill; (ii) making orientation markingon a member located in an inner tube of a drill string during saiddrilling, the marking being made by a non-magnetic ball located in theinner tube and indication the lowest portion in the plane of the memberwhen the core was separated from the substrate; (iii) removing the innertube and core from the drilled substrate; (iv) relating the orientationmarking to the orientation of the core.
 13. The method for determiningthe orientation of a drilled core relative to a substrate comprising:(a) drilling a core from a substrate with a core drill; (b) making anorientation marking on a member located in a inner tube of a drill stingduring said drilling, the marking indicating the lowest portion in theplane of the member when the core was separated from the substrate; (c)removing the inner tube and core from the drilled substrate; (d)relating the orientation marking to the orientation of the core by: (i)determining the angular orientation of the member relative to the innertube; (ii) observing the angular displacement of the marking relative toan index of the inner tube; (iii) aligning the core to a knownrelationship with the inner tube; then (iv) marking the coer inaccordance with the observed angular displacement by transferring saidangular displacement from the inner tube of the core by: (v) using aspirit level to orientate the inner tube so that a known index isvertically upright; (vi) using a second spirit level to verticallyorient the member, the visual mark relating to the index mark; and (vii)transferring the orientation of the orientation marking from the memberto the core.
 14. The method for determining the orientation of a drilledcore relative to a substrate comprising: (a) drilling a core from asubstrate with a core drill; (b) making an orientation marking on amember located in an inner tube of a drill string during said drilling,the marking indicating the lowest portion in the plane of the memberwhen the core was separated from the substrate; (c) removing the innertube and core from the drilled substrate; (d) relating the orientationmarking to the orientation of the core by: (i) aligning a laser beamwith a first index formed on an exterior of the inner tube; (ii)discharging the beam in the direction of and along the length of thecore or core tube; (iii) using the beam to mark the core or core tubewith a second index mark which aligns with the first index mark; and(iv) measuring core orientation information from the member; thentransferring the information to the core using the second index mark asa reference.
 15. The method for determining the orientation of a drilledcore relative to a substrate according to claim 14, wherein aligning thelaser beam with a first index comprises: retaining a laser light sourceon a mount, the mount having a key, the first index corresponding to akeyway; and locating the key in the keyway.
 16. An upper end for theinner tube of a core drill comprising: a spindle supported within acylindrical casing; a shield adapted to engage a portion of the innertube of the core drill; a pendulum suspended within the shield andmechanically linked to the spindle, and an impressionable washer locatedbelow the pendulum and indexed to the casing, and  wherein the spindlesupported within the casing for reciprocating motion and biased, by aspring in a casing, such that tension on the spindle overcomes the biasand causes the pendulum to make an impression on the washer, andwherein: the spindle is split and has upper and lower portions; the twoportions are joined by a coupling; the lower portion rotatesindependently of the upper portion; and the coupling transmittingtension from the upper portion to the lower portion.
 17. An upper endaccording to claim 16, wherein: the pendulum comprises an axially rigidmember, suspended by a ball and socket arrangement, the pendulumterminating in a point which can make an impression on the washer. 18.An upper end for the inner tube of a core drill according to claim 16,wherein a lower end of the casing surrounds and restrains a spindlecoupling.
 19. An upper end for the inner tube of a core drill accordingto claim 16, wherein the washer is retained within a needle chamberwhich is carried by the spindle.
 20. An upper end for the inner tube ofa core drill according to claim 16, wherein: the coupling supportsthrust bearings which impose on an integral flange formed on the top ofthe lower portion.
 21. An upper end according to claim 16, wherein: alower end of the casing supports seals between the spindle and thecasing.
 22. An upper end for the inner tube of a core drill according toclaim 16, wherein the coupling supports two thrust bearings, one locatedabove the flange and one below the flange.
 23. An upper end according toclaim 16, wherein: the spring surrounds the spindle and extends betweenan upper extent of the casing and a nut which is threaded onto thespindle.
 24. An upper end according to claim 16, wherein the couplingsupports two thrust bearings, one located above the flange and one belowthe flange.